Air Pollution

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Transcript of Air Pollution

Air PollutionAir Pollution"The introduction of chemicals, particualte matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials or alter ecosystems"Photochemical smog continued"EPA says Half of the United States Is Breathing Excessive Levels of Smog"Pollution ControlAll about "O" threeUV-A UV-B UV-CCan occur naturally or be anthropogenicAtmosphere is a global systemA "commons"Photochemical Oxidants"Ozone"

Particulate MatterLeadCarbon OxidesNitrogen OxidesSulfur DioxideThe Big SixComes from coal and oilrespiratory irritantexacerbates asthmaacid rainNatural sources:VolcanoesForest FiresNOxBecause they can either be nitrogen oxide NO or nitrogen dioxide NO2NO: colorless and ordorlessNO2: pungent, reddish-brown gasFossil fuels are the most common sourceNatural sources:forest fires, lightning, microbial action in soil**Plays a role in forming tropospheric ozone and photochemical smog and acid rain**CO: colorless, odorless gas formed during incomplete combustion of most matterCO2: colorless, odorless gas. Formed during complete combustionBetter than CO for human healthInterferes with O2 transport in the bloodlow concentration: headachehigh concentration: deathGreenhouse gas, increases earth's global tempsolid or liquids suspended in the airrange in size from .01 micrometers to 100 micrometersPM-10 (less than 10 micrometers cause most concernNot filtered out by the nosedeposits into the lungsusually made up of more toxic chemicalscans cause "haze" or reduced visibilityOxides: remove electrons from other compoundsSunlight + NOx --> photochemical oxidants (O3)harmful to plant tissue, human respiratory tissue, and construction materialOzone: O3, well known photochemical oxidantO3 + Particulate Matter --> SmogSmog = smoke + fog2 types of smog:photochemical smog (Los Angeles-type or Brown)dominated by oxidantssulfurous smog (london-type or gray)sulfur compoundsuse to be added to gas to improve performanceThe Clean Air Act1970Like the clean water act, regulates how much of certain pollutants could be in the atmosphereCalled National Ambient Air Quality Standards or (NAAQS)Not so much of a problem anymore as we don't add lead to gasHence- "unleaded"~June 2010http://www.epa.gov/airnow/ozone/o3.htmlControl of Sulfur and Nitrogen OxideSulfur: Fluidized bed combustion:burning coal close to CaCO3Sulfur is absorbedCaCO3 + Sulfur --> sheetrockClean Air Actbuying and selling allowanceseach year, allowances reduced1982 (26 million tons)2008 (11.4 million tons)Free market determines cheapest way of controlling sulfur emissionsNitrogen:1975, all cars to contain a catalytic converterContain platinum and palladiumThe reason for no Lead in gasReduces NOx and CO emissionsControl of SmogDrastic measures:Suburbs and wood-burning stoveslighter fluids and barbequesCalifornia and BakeriesReduce VOCsmore O3, but less Photochemical oxidentsCars (emit NOx and VOCs):Mexico city license plates2008 Beijing Olympicsimproved public transportationshut down industryDo The MathGiven the data presented below for total SO2 emission reductions in the United States, calculate the total percentage reduction and the annual percentage reduction of SO2 emissions26 million tons in 198211.4 million tons in 2008TroposphereStratosphereFormation and Breakdown of Stratospheric OzoneAnthropogenic Contributions to Ozone DestructionEfforts to Reduce Ozone Depletion1. UV-C breaks bonds holding together O2Creates two "O" moleculesO2 + UV-C --> 2O2. Oxygen reacts with free oxygen atomsO2 + O --> O33. Ozone breaks down into O2 and Free Oxygen when absorbing UV-C and UV-BO3 + UV-B/UV-C -->O2 + O4. Those products may again form O3Chlorine the Ozone killerchloroflourocarbons (CFCs)CFCs were ideal for many purposes:refrigerationair conditioningaerosol cans (propellant)"blowing agent" (inject air into Styrofoam)CFCs are:extremely stablenontoxicnonflammableIn the Stratosphere:1. UV breaks the Chlorine Free2. The Ozone reactsO3 + Cl --> ClO + O23. A free oxygen atom reacts with ClOO + ClO --> Cl + O24. Chlorine is once again produces, so it can continue to break down ozone without changing or getting "used up"mid-1980s, researchers noticed ozone depletion, starting in 1979Decreased O3 means Increased UV radiation hitting earthCase-study of problem solving1986, many nations meet in Montreal success seemed unlikelyeconomically staggeringdebate over CFCs role in O3 depletionSurprisingly, 27 nations signed Motreal Protocol50% reduction of ozone depleting compounds by the year 2000Crisis AvertedIndoor Air Pollutiondeveloping countriesdeveloped countrieswood, animal manure, coal as energy sourceslittle to no ventilation in the home1.6 million deaths per year 56% of those are under 5 years oldPeople in developing countries spend much more time indoorshomes are more insulatedplastic and petroleum -based products give off chemical vaporsAsbestosCarbon MonoxideRadon-222VOCs in Home ProductsSick Building SyndromeLong, thin, fibrous silicate mineralFound in insulation material steam & hot water pipes Shingles & siding on buildingsExposure can cause lung cancermalfunctioning of exhaust systems from household heatersUsually Natural GasCO binds with hemoglobin in the bodyCan cause deathNaturally occuring radioactive gasMost common source is from graniteMight want to rethink those granite counter tops...water in contact from underlying rocksthrough cracks in the foundationRadon can attach to dust particles and be inhaled21,000 people die every year from radon causing lung cancersecond leading cause of lung cancer aside from cigarette smokingBest ways to prevent it:seal cracks in the basementimprove ventilation in the homeMany VOCs are found in building materialsWorst of the worst: FormaldehydeFound in particle board and carpeting glueIt's that nice "new home" or "new car smell"can cause eye & throat irritationsalso a suspected carcinogenTo prevent heating and cooling costs, buildings have become more and more insulatedCauses a build up of toxins and pollutants in an airtight spaceSick Building Syndrome: a general terms for the maladies associated with new, insulated buildingsSymptoms:headachesnauseathroat or eye irritationfatigueEPAs four causes:inadequate ventilationchemical contamination from gluescarpetingfurnitureOutdoor sources Vehicle exaustBiological contaminationPollen and Moldcleaning agentscopy machines